A novel method for sensitive determination of chloride anion at multilayer nano-silver modified indiumtin oxide (ITO) electrode has been developed. The multilayer films were fabricated via self-assembly/electrochemical-assembly methods, in which the 3-aminopropyltriethoxysilane (APTS) was used to modify ITO conducting glass, layer-by-layer (LBL) method was applied to prepare the multilayer films and poly (diallyldimethylammonium chloride) (PDDA) was employed as a bridging ligand. The resulting electrode (Ag/{PDDA/Ag}(m)/APTS/ITO) surface was characterized with SEM and UV-vis. The electrochemical behavior of Cl- at the Ag/{PDDA/Ag}(m)/APTS/ITO electrode was studied by cyclic voltammetry. The results indicated that the modified electrode exhibited substantial enhancement in electrochemical sensitivity for Cl- due to its large surface area and particular absorbability. The Ag/{PDDA/Ag}(m)/APTS/ITO electrode detected Cl- by voltammetry based on the oxidation of Ag/Cl- that generated from a specific reaction of chloride ions with nano-silver. After accumulation of 3 min for Cl- at Ag/{PDDA/Ag}(m)/APTS/ITO electrode, the peak height (Ag/Cl-) increased linearly with the concentrations of Cl- in the range of 1.0 x 10(-8)-1.0 x 10(-6) mol L-1. The detection limit was 5.2 x 10(-9) mol L-1 at 3 sigma level. This modified electrode could be successfully applied in water samples with low cost and high sensitivity. (C) 2011 Elsevier B.V. All rights reserved.